Among known splicing methods for spun yarns, there can be mentioned a method in which both the yarn ends to be spliced are first untwisted and then overlapped and the overlapped portion of the yarn ends are subjected to the action of a compressed fluid, whereby the yarn end portions are mingled together and fibers of both the yarn ends are entangled with one another to effect splicing.
In U.S. Pat. No. 4,263,775, I proposed a splicing method in which the splicing operation occurs in a splicing apparatus. In order to promote entanglement of the overlapped portion of two yarn ends and obtain a beautiful joint having a certain length, the yarns of the overlapped portion are untwisted to produce a condition suitable for splicing. More specifically, according to this method, each yarn end is clamped at a point a certain length from the yarn end. Both the yarn ends are sucked in suction nozzles arranged on both the sides of the splicing hole. The yarn ends are acted upon by air streams turning in the nozzles in a direction so as to untwist the yarn ends to disentange and separate fibers of the loose portions of the yarn ends. The yarns in the suction nozzles are then taken out by a yarn gathering lever and are inserted into the splicing hole.
In this method, loose parts of fibers disentangled in the suction nozzle are separated from the fiber bundle and are sucked into the nozzle. Therefore, the length of the disentangled yarn end left in the nozzle differs according to the length of fibers not removed from the yarn. More specifically, in the case of a yarn having a long fiber length, the length of the yarn end left in the nozzle is extended by the length of those fibers retained in the yarn. In the case of a yarn having a short fiber length, most of fibers are separated and the length of the yarn end left in the nozzle is shortened to that equivalent to the fibers retained as part of the yarn. Accordingly, when the yarn ends are taken out from the nozzle, the length of the untwisted and disentangled portion differs for each yarn end depending on fiber length. As a result, the length of the overlapped portion may be different for each yarn end. If the length of the overlapped portion is too long, the action of the swirling fluid stream in the splicing hole is not exerted on the loose end portion of the yarn end, resulting in formation of horny projections on both the ends of the resulting joint. These horny projections may be caught and broken by a knitting needle when the yarn is used in a knitting step to fabricate cloth. The quality of the resulting knitted fabric may thereby be degraded. If the length of the overlapped portion is too short, splicing entanglement is caused only in the extreme end portion of the yarn end where the strength of the joint is decreased.